1. History of Abhidhamma2. Names of books of Abhidhamma Pitaka and their commentaries3. Differences of contents of Sutta and Abhidhamma Pitakas4. Differences between Paramasacca and sammuti sacca (absolute & conventional realities)5. The 4 Absolute Realities (Paramatthas)6. Classification of citta into 89 or 121 types